1. Field of the Invention
The invention in general relates to helmets, and more particularly, to swimmable diving helmets.
2. Description of the Prior Art
Swimmable diving helmets are generally tailored and built for an individual diver to insure the maximum comfort when the diver is working under water. The customizing may be accomplished in a variety of ways -- one of which is to fit pads onto the inner surface of a helmet. This approach adapts each helmet to an individual; however, each helmet built may be used only by the individual to whom it is fitted, and if a next diver wants to use the same helmet, it must be refitted or else the diver would suffer a poor fit which could cause painful pressure points and which could also allow his head to move within the helmet.
Diving helmets are fabricated with a sealing mechanism to maintain water-tight integrity. One type of sealing arrangement utilizes a neck-seal, and in use with a breathable gas being supplied to that helmet, there is a tendency, in various situations, for the helmet to lift off the diver's head due to a piston effect. In many prior art arrangements, this effect has been neutralized by arrangements resulting in discomfort to the diver.
When utilized in the swimming position, various helmets, particularly those in which the head is free to move, result in objectionable neck straining movements by the diver in order to counteract rotating couples due to buoyancy considerations.